JOHANNESBURG, Sept. 7 (Xinhua) -- A power outage across Johannesburg also caused a blackout at ailing former president Nelson Mandela's home, authorities confirmed on Saturday.

Mandela's home was among those hit by widespread power outages in Johannesburg this week, electricity utility City Power said.

But electricity has been restored to the Houghton Estate where Mandela's house is located, said City Power spokesperson Sol Masolo.

It remains unknown whether the outage affected the treatment of Mandela, who was released from hospital on Sept. 1 after a lengthy stay for a recurring lung infection.

Mandela's home has been reconfigured to suit the medical requirement, and the medical intensive care team in the hospital is now with Mandela in his house to give him timely treatment, according to the presidency.

Mandela's condition was at times unstable, but he was responding to treatment, the last official update on his condition said.

The widespread power outage was the result of a strike by municipality workers who downed tools on Wednesday over a new shift structure which was meant to improve service delivery.

During the strike, some workers "sabotaged" sub-stations around the city, an act described by officials as "terrorism."